This product combines 240 mg of standardized 80% Silymarin extract with 1260 mg of Organic Milk Thistle Seed (which contains flavenoids, amino acids, proteins and fats which help the body absorb the otherwise-difficult-to-absorb Silymarin). The seed typically contains only 4-6% of Silymarin, which is the liver-protective component, so their 3-capsule-serving contains anywhere from 290mg to 315 mg of Silymarin. The dosage you want will depend on the condition for which you are taking Silymarin. Milk Thistle interacts with a number of drugs and supplements (including Vitamin E and Iron), so do a Google search to be sure you use this safely.